Polyesters of 2-ethylhexanediol-1, 3



Patented June 27, 1 950 POLYESTEBS OF 2- William M. Lanham, Charleston, W. Va., aaignor,

by mesne assignments, Carbon Corporation, a corporation of New York No Drawing. Application May 20, 1947, Serial No. 749,357

Claiml. (cl- 260-485) This invention relates to plasticizers which are polyesters of 2-ethylhexanediol-L3 with dibasic acids.

At present, the bulk of the plasticizer requirements for vinyl resins and cellulose derivatives is satisfied with relatively non-volatile esters of simple molecular structure, such as di(2-ethylhexyl) phthalate. While these simple esters possess considerable advantages for this purpose, the combination of resin and plasticizer is not as permanent as is desired, since gradual loss of plasticizer occurs by evaporation or by extraction with liquids which may come in contact with the plasticized resin. Furthermore, the simple ester plasticizers are active solvents for many substances, and they tend to migrate from the plasticized article to other materials which touch the plasticized article.

It has been found that liquid (1. e. capable of gravitational flow at 30 C.) polyesters of 2-ethylhexanediol-1,3 with saturated aliphatic dicarboxylic acids containing from four to ten carbon atoms, which polyesters have an average molecular weight of at least 500, and preferably from 1000 to 2000, are permanent plasticizers for vinyl resins and cellulose derivatives. The new polyesters are to be distinguished from the acetylated polyesters of ethylene glycol, diethylene glycol and triethylene glycol with succinic acid known in the art, in that the polyesters of 2-ethylhextreatment makes the anediol-1,3 are highly compatible with vinyl chloride resins, whereas the known polyesters derived from the simple glycols and polyglycols are quite incompatible with these resins.

The polyesters of 2-ethylhexanediol-L3 and dibasic acids are preferably prepared by reacting an excess of the diol with the dibasic acid, that is, the molar ratio of diol to dibasic acid being greater than one so that the ,final products contain free hydroxyl groups. The average molecular weight of the polyesters may be controlled by regulating the molar ratio of the diol to the dibasic acid charged to the reaction vessel. Thus, the following data have been observed in the reaction of 2-ethylhexanediol-1,3 with succinic acid.

Molar Ratio 'fig gg lg Range of Polyester to Union Carbide and 2 polyesters more miscible with vinyl chloride resins and reduces any loss of plasticizer by water extraction from elasticized articles, such as shower curtains.

The chain length of the particular dibasic acid used in forming the polyesters influences the properties of the resulting plasticizer. Shortchain acids, such as succinic and adipic acids, re-

suit in plasticizers having good resistance to oil extraction but the plasticized articles tend to become somewhat inflexible at low temperatures. On the other hand, plasticized articles containing polyesters made from acids of longer chain length, such as sebacic acid, have better flexibility at low temperatures, although their resistance to extraction by oils is usually not as good. A compromise between low temperature flexibility and oil resistance of the plasticized articles can often be obtained by using mixtures of succinic acid and adipic acid or mixtures of succinic acid and sebacic acid. 1

The flexibility at low temperatures of articles plasticized with polyesters derived from succinic acid can be improved by substituting a polyethylr ene glycol, such as tri-, tetra-, penta-, or hexaethylene glycol, for part of the 2-ethylhexanediol-1,3.' The molar ratio of the polyglycol to the diol should not exceed 1 to 5, because at higher ratios the polyesters become less compatible with vinyl chloride resins. As an exception, if adipic acid is used in making the polyesters, the molar ratio of the polyglycol to the diol may be higher than 1 to 5, for instance, 1 to 2.

The following compatibility data have been determined by examination of films cast from solutions of the resins and a fully acetylated polyester of succinic acid and 2-ethylhexanediol-1,3

gigs/ting an average molecular weight of about Ratilo of Rtesin to o Resin yes r Cellulose nitrate. V; See. R. S C C C C 0 SI 0 C O C C C copolymer C C a C Vinyl lchloride, vinyl acetate, 10%;

copo ymer C C 0 Vinyl chloride. 97%; vinyl acetate, 3%;

copolymer C C C Vinyl chloride, 87%; maleic acid, 1%;

vinyl acetate 12%; copolymer C 0 C Chlorinated rubber (low viscosity)- 0 c o Cellulose aoetate-butyrate SI SI I Cellulose Acetate I I I Ethyl Cellulose (low viscosity) SI I I Polystyrene I I I Polyvinyl butyral $1 I I o com atlble-clear mm? SI=slig tly incompatible-hazy film.

l-ineompatible c oudy to cheesy film.

out by heating the polyester bearing hydrox'yl" groups with an excess of the fatty acid anhydride. After completion oi the reaction, low boiling materials are stripped irom t e P lyester by heating the product at reduced pressures.

The following examples will further iilmtrate the invention:

EXAMPLE! Two mols oisuccinic anhydride (200g'rams). three mols oi 2ethylhexanediol-1.3(433 gram), and 500 c. c. of benzene as the aseotrope former. were refluxed sixteen hours in a still with a decanter head. At the end of this timeten drops of concentrated sulfuric acid were added and refluxing continued for sixteen hours longer. During the whole aterflication about 43 c. c. of water, which is slightly more than the theoretical amount, were collected. The benzene was flashed oil under vacuum and the resulting residue was washed with water until neutral. After careful stripping of the residue in a falling film type stripping still, a yellow liquid was obtained'havin'g a molecular weight of 886 by the Menzies-Wright method. (J. Am. Chem. Soc. 43, 2314, 1921.) It was compatible with vinyl chloride (95%) vinyl acetate (5%) copolymer at 33% concentration of the polyester by weight of the composition. but after 41 days at room temperature some exudation of plastlelser was noticeable.

The tree hydroxyl groups of this plasticmer were reacted with z-ethylhexanoic anhydride by heating some of the plasticiser (144 grams) with an excess of 2-ethylhexanoic anhydride (134 grams) at 150 C. for 4.5 days. All low boiling materials were then stripped oil in a falling fllm' type st ippin still to give a brown liquid prod molecular weight 912 by the Menzies-Wright method, which was compatible with vinyl chloride (95%) vinyl acetate (5%) copolymer at 33% concentration of the polyester by weight of the composition. The plasticlser did not exude on aslns.

EXAMPLE 2 Nine mols oi succinlc anhydrlde (900 grams) and 10.8 molsoi 2-ethyl-L3-hexanediol (157'! grams) were heated together from 100 C. to 220 C. with a slowstream of nitrogen passing through the reaction mixture to carry 01! water as fast as formed. No catalyst was required at these temperatures and after about 24 hours of heating the water evolution had ceased. Further heating for eight hours at 220 C. and mm. pressure followed by processing in a falling dim type stripping still gave product, light yellow in color, with a molecular weight of 1227 by Menzies-wright method. It was compatible with vinyl chloride (95%) vinyl acetate (5%) copolymer at 33% concentration by weight oi the polyester.

The free hydroxyl groups of the polyester were acetylated by heating 300 grams of the polyester with 500 grams of acetic anhydride for 16 hours on a steam bath. After this time acetic acid and excess acetic anhydride were removed at 100 C. and less than one mm. pressure. Final stripping was carried out in the railing film striping still at. 150 c. and less than one mm. pressure.

Theresulting plasticizer was a light yellow liquid compatible with vinyl chloride vinyl acetate'. (5%) copolymer at 33% concentration.

2-ethylhexanoy1 groups were also introduced in the molecule by heating 250 grams. of the original polyester with 400 grams of Z-ethylhexanolc anhydrlde at 125 C. for 48 hours. All low boiling material was removed on the falling mm stripper at 180 C. and less than one mm. pressure. This plasticizer also was compatible with the same vinyl copolymer at 33% concentration by weight of the polyester.

EXAMPLE3 A general procedure useful for the preparation of 2-ethyl-L3-hexanediol succinate acetate on a large scale is illustrated by the following example:

' Apparatus The apparatus used was a stainless steel still consisting of a kettleof 50 to 60 gallons capacity,

-a iractionatlng column. a short goose-neck column and a condenser. The liquid return line from the condenserlat the top of the iractionating columnwas so arranged that the water removed from the reaction mixture with a refluxing inert solvent could be decanted. The apparatus was arranged so that the vapors from the still could pass through either the Iractionating column or the goose-neck column, depending on which one was blocked-oil.

Charge 175.7 lbs. of 2-ethylhexanediol-l,3 (1.2 pound mols) 118.1 lbs. of succinic acid (1.0 pound moi) 90.0 lbs. of dibutyl ether (azeotrope former) Procedure The"goose-neck column attached to the kettle was blocked-oil. and the charge added to the kettle. The kettle temperature was slowly raised to 190 C. and maintained at this temperature. It was necessary to distill oi! some oi? the dibutyl ether while the temperature was being raised in order to avoid flooding the column. After a total time of approximately 36 hours, apparently no water was being formed and analysis indicated that the esteriiication was complete. The dibutyl ether was removed by distillation under reduced pressure and then 50.0 pounds of acetic anhydride were added to the kettle. The kettle temperature maintained at to C. during this acetylations Analysis 01' samples from the resigction mixture taken from time to time indicated that the acetylation was complete in somewhat less than eight hours.

The fractlonatlng column was then blocked-oil and the goose-neck column opened. The reaction mixture was then stripped at C./5 mm. using this short column. When the acidity of the residue reached a value of less than 0.1 c. c. N KOH/sa, the heating was stopped, the still vented, and the residue filtered while hot.

Properties i'he final product was a thick liquid having a viscosity of 88.600 cp. at 20 C. and 2,239 on. at 50 C. and an average molecular weight (Menzies- Wright) of 1285. The specific gravity was 1.080 and the refractive index no" was 1.4637.

When evaluated with a vinyl chloride (97%) vinyl acetate (3%) copolymer having an average molecular weight of about 24,000, it was found that the plasticizer was 46.4% effective, 1. e. a concentration of 46.4% of the plasticizer based on the total weight oi resin plus plasticizer produced an elastomer having an elongation of 100% at 25 C. under a load of 1000p. s. i. (applied at a constant rate in 74 sec.). At this concentration the flex temperature (Ta) was --9 C. [The flex temperature is a measure of pliability and is defined as the temperature which yields an apparent modulus of elasticity of 135,000 p. s. 1. according to Clash and Berg. (Ind. Eng. Chem. 34, 1218, 1942.)] The tensile strength at the same concentration of plasticizer was 2200 p. s. i.. and the ten day extraction loss from a 0.004" fllm at 27 C. was 0.93% in water and 3.4% in mineral oil. There was no exudation of the plasticizer on aging at room temperature.

'EXAMPLE4 The plasticizer described in Example 3 was employed in making plastic compositions oi ditferent types by milling copolymers of vinyl chloride and vinyl acetate with the plasticizer and other ingredients. The polyester plasticizer did not migrate from the plasticized articles to other materials in contact with the articles and the polyester was not appreciably extracted by oil. In these respects, the new plasticized articles were superior to the commercial composition based on di(2-ethylhexyl) phthalate plasticizer.

A. Injection molding composition (all percentages bilweiaht) Per cent Copolymer of vinyl chloride, 96%; vinyl acetate, 4% 49.75 Polyester plasticizer 26.75 Lead silica 2.00 Mineral ofl 1.50 Calcium carbonate 15.00 Iron oxide, red 2.00 Carbon black. 0.50 Brown pigment 2.00 Red pigment 0.50

B. Extrusion composition (all percentages by weight) 1 Per cent Copolymer of vinyl chloride, 96%; vinyl acetate, 4% 48.4 Polyester plasticizer 39.6 Calcium stearate 1.0 Dibutyl tin laurate-maleate 1.0 Aluminum-hydrate 10.0

C. Sheeting 12 mil, useful as a container for compass oil Per cent Copolymer of vinyl chloride, 96%; vinyl n. Calendered film-4 mil-useful as a backing for pressure sensitive adhesive tape Per cent Copolymer of vinyl chloride, 96%; vinyl acetate, 4% 55.0 Polyester plasticizeni 43.0 Dibutyl tin laurateemaleate 1.5 Btearic acid 0.5

EXAMPLE 5 Three mols oi adipic acid (438 grams), three and six-tenths mols oi 2-ethylhexanediol-1,3(526 grams) and 400 c. c. of xylene as the azeotrope i'ormer were heated together for about 18 hours after which time no further water was evolved and the acid number had reached a minimum value of about 10. The reaction mixture was then pot stripped to 180 C. at 1.5 mm. pressure. The resulting polyester was compatible at concentration with vinyl copolymers of the type described in the previous examples.

In order to acetylate the free hydroxyl groups, 631 grams of the above polyester were heated for 48 hours at 100 C. with 230 grams of acetic anhydride. After pot stripping to 180 C. at 1 mm. pressure the residue was carefully stripped on the falling film stripper at 180 C. and 0.2 mm. pressure. The product was an amber colored liquid which milled readily with vinyl chloridevinyl acetate copolymers at 45% plasticizer concentration.

EXAMPLE 6 A plasticizer similar to the acetylated polyester described in Example 5 was utilized in electrical insulation. The composition (per cent by weight) was as follows:

' Per cent Copolymer of vinyl chloride, 97%; vinyl This composition had a volume resistivity at C. of 3.7xl0 megohm-cm. The resinous plasticizer, as compared to di(2-ethylhexyl) phthalate, is much more non-volatile, resulting in compositions which can withstand elevated temperatures for longer periods without stiffenins.

EXAMPLE 7 A sebacate polyester corresponding to the adipate described in Example 5 was prepared by reacting 5 mols of sebacic acid (1011 grams) with 6 mols of 2-ethylhexanediol-1,3 (877 grams) under the same operating conditions. The unacetylated polyester was only partly compatible with vinyl chloride-vinyl acetate copolymer at 45% concentration since a clear sheet was not obtained.

Acetylation of hydroxyl groups was accomplished by heating 869 grams of the polyester with 160 grams of acetic anhydride at 100 C. for 24 hours. The product thus obtained was compatibleat 45% concentration with vinyl chic- 100.0 13 ride-vinyl acetate copolymer.

esters and of plastic composition comprising polymers of vinyl chloride, (98%) and vinyl acetate (4%) plasticized with the polyesters are given below, all percentages being by weight.

Plasticizer Plastic Composition with Vinyl Copolymer I Per Cent Extraction Di 1 M018 M018 Visa, Eil'ectve- T 0 s'tlensiie from .004" film 25 C.

o s ness er I rength Add 15 0. 06m p. s. 1.

In Water In Oil 2-ethylhemnediol-i 3 1.0 l,l0-decanediol 0. 2 1 1. 0 1, 574 45. 6 9. 5 2150 0. 28 2. 6 z-etbylhexanedioi-l 1. 0 trlethylene giyc0i-. 0. 2 l l. 0 l, 430 48. 6 i2 5 202) 0. 72 l. 9 2-ethylhexanedio1-li3. l. 0 tetraethylene glyco 0. 2 l 1.0 1, 074 47. 8 -14. 5 2000 2. 51 6.0 tethylhexanediol-lfi... 0. 8 triethylene glycol- 0. 4 I l. 0 590 42. 0 18. 7 242) 2. 03 4. 8

1 Succimic acid. 1 Adipic acid.

and two and four-tenths mols of 2-ethylhexanedbl-1,3650 grams) with xylene as the azeotrope former for removing water. After heating the mixture for about 24 hours at 150 to 160 C. O

the reaction was complete. The product was carefully stripped in a pot still and in the falling film stripper at 180 C. and 0.5 mm. The polyester was acetylated by heating 515 grams of the polyester with 115 grams of acetic anhydride at 100 C. for 24 hours. The product was an amber colored liquid compatible with vinyl chloridevinyl acetate copolymer at 50% concentration.

EXAMPLE 9 Poluesters of 2-ethylhexanediol-L3 with various dibasic acids and mirtures thereof 01' the foregoing examples, No. 9 demonstrates the eflect of the chain length of the dibasic acid on the properties of the polyester and No. 10 lllustrates the modifications obtainable by replacing part of the 2-ethylhexanedioi-1,3 with another diol. However, the acetylated polyester of 2-ethy1hexanediol-l,3 with succinic acid or anhydride has a favorable combination or properties, and can be made from cheap, readily available materials.

We claim:

1. Liquid polyesters of 2-ethylhexanediol-l,3 with aliphatic saturated dicarboxylic acids having from four to ten carbon atoms, said polyesters having an average molecular weight of at least 500.

2. Liquid polyesters of 2-ethylhexanediol-l,3 with aliphatic saturated dicarboxylic acids having from four to ten carbon atoms, said polyesters containing free hydroxyl groups and having an average molecular weight of from 500 to 2000.

'3. Acylated liquid esteriflcation products of aliphatic saturated dicarboxylic acids having from four to ten carbon atoms with more than one mol of 2-ethylhexanediol-1,3 per mol of acid,

Plasticizer Plastic Composition with Vinyl Copolymer E11 11 lensil 3 tttifiitt Mon Mols Viscosi D101 Acid Add 0p" ne ea T 0.1 Sign- :11,

In Water In Oil 0. 0 1,491 4m -11.3 1, 740 0. 21 1. a7 1.1 1.0 m m -105 2,010 0.22 0.83

r g 2,209 4114 9 2,200 0.93 3.1 0Z1 0,015 41. 0 -a 1, 000 031 2 14 1. 2 1.0 m 41.5 -as 2, 120 0.80 19.8

1 For definition see Example 3.

EXAMPLE 10 said esteriflcation products before acylation hav- Poluesters of mixtures of z-ethylhexanediol-i ,3 g g zz gfifi ig zf z ggg of 3 35 8:: and glucols with dibdsic acids y p ted p ing a fatty acyl radical containing from two to eight carbon atoms.

4. Acetyiated liquid esteriflcation products oi aliphatic saturated dicarboxylic acids having from four to ten carbon atoms with more than one mol of 2-ethylhexanediol-1,3 per mol of acid,

dibasic acid and certain properties oi the polysaid esteriiication products before acetylation having an average molecular weight of at least 500.

5. An acetylated liquid esteriflcation product of succinic acid with more than one mol of 2- ethylhexanediol-L3 per mol of acid, said esterlfication product before acetylation having an average molecular weight of at least 500.

6. An acetylated liquid esteriflcation product of adipic acid with more than one mol of 2-ethylhexanediol-L3 per mol of acid, said esteriflcation product before acetylation having an average molecular weight of at least 500.

7. An acetylated liquid esterification product of succinic acid with more than one mol of a dlol mixture per mol of acid, said mixture consistin of 2-ethylhexanediol-L3 and a liquid polyethylene glycol, the molar ratio of 2-ethylhexanedlol- 1,3 to the polyethylene glycol being at least 5 to 1 and said esteriflcation product before acetylation having an average molecular weight of at least 500.

8. Process of making liquid polyesters which comprises heating 2-ethylhexanediol-1,3 with one of the group consisting of aliphatic saturated dicarboxylic acids having from four to ten carbon atoms and their anhydrides, the molar ratio of said diol to said acids or said anhydrides being from 1.01 to 1.50.

9. Process of making liquid polyesters which 10 comprises heating 2-ethylhexanedlol-1,3 with one of the group consisting of aliphatic saturated dicarboxylic acids having from four to ten carbon atoms and their anhydrides, the molar ratio of said diol to said acids or said anhydrides being from 1.01 to 1.50, to form hydroxyi compounds, and thereafter reacting said hydroiwl compounds with the anhydride of a fatty acid, the fatty acid being one which contains from two to eight carbon atoms.

10. Process of making liquid polyesters which comprises heating one mol of succinic anhydride with from 1.01 to 1.50 mols of 2-ethylhexanediol- 1,3 to form hydroxyl compounds, and thereafter reacting said hydroxyl compounds with acetic anhydride.

WILLIAM M. LANHAM.

REFERENCES CITED The following references are of record in the file of this patent:

l UNITED STATES PATENTS Number 

1. LIQUID POLYESTERS OF 2-ETHYLHEXANEDIOL-1,3 WITH ALIPHATIC SATURATED DICARBOXYLIC ACIDS HAVING FROM FOUR TO TEN CARBON ATOMS, SAID POLYESTERS HAVING AN AVERAGE MOLECULAR WEIGHT OF AT LEAST
 500. 